hi linux qurues

i have ias-server in my office ,ican connect net sucessfully in firefox ferdora 6, but i could not connect internet messenger in it ,itried my best but fail.
i use following entries plz ckeck where i am wrong

IN BASIC

protocole = MSN
screen name = farnaw@hotmail.com
password = *****
alis = farooq

IN ADVANCE

login server = 192.168.0.254 ( this is my isa server)
port = 8080
( )use HTTP Method
( )show custom smileys

proxy type = it has 6 options (HTTP
No prox
i dont know which option socks 4
is to use socks 5
use global proxy settings
use environmental settings
when i select any one option from proxy type it returns following options i fills as folowing

host = 192.168.0.254
port = 8080
username = farnaw@hotmail.com
password = ******

it returns errors

" connection error from notification server. reading error"
" Also returns port 502 error somtime "



plz help me
thanks in advance

farnaw